An example of this type of shift lever position sensor of the prior art is described in Japanese Laid-Open Patent Publication No. 1-87946 (Japanese Laid-Open Patent Publication No. 64-87946).
In this shift lever position sensor, when a first electrical signal is emitted as a result of only one of a plurality of switching devices of a shift lever position sensor being closed, a CPU writes the corresponding position data into a memory device. When only one of the switching devices of the transmission is emitting an electrical signal of a first level L of switch closing, the CPU writes the corresponding position data into memory, and these are used as control parameters of the transmission.
In the above-mentioned apparatus, when two or more switching devices emit a signal of a first level or all switching devices emit a signal of a second H level, and a signal error continues for a prescribed period of time with the vehicle speed according to the signal of a vehicle speed pulse generator being equal to or greater than a prescribed value, an error warning occurs and a warning is emitted by a shift lever warning lamp.
In addition to there being a plurality of switches in the above-mentioned prior art, a CPU is required, thus resulting in the disadvantages of having a complicated constitution and being expensive.